Q4 of 24 Page 227

If the height and slant height of a cone are6cm.and 10cm. respectively, then let us determine total surface area and volume of the cone.

Height, h = 6 cm


Slant height, l = 10 cm


∴ radius, r = √(l2 – h2) = √(102 – 62) = √(100 – 36) = 8 cm


∴ Total surface area,


= πr2 + πrl


= 22/7 × 82 + 22/7 × 8 × 10


= 201.14 + 251.43


= 452.57 sq. cm.


∴ volume,


= πr2h/3


= 22/7 × 82 × 6/3


= 402.28 cubic cm


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